Playing the al Qaeda Card

The question is why would al-Qaeda provoke the Shiite to violence? And why does that justify our troops remain? They are not provoking U.S troops. It seems that because the Sunnis are the underdogs now, they are not experiencing the representation they once had in the government, so they are violently lashing out against the Shiite. And it was said that PM Maliki is making moves within the Iraq government such as moving Sunnis out of positions and replacing them with Shiites. If they are a threat to the U.S. they would be attacking our troops. Yes we do suffer casualties but I would have to put our casualties in the innocent bystander category. Our troops are just on the sidelines.